Lately, my avatar picture is not showing up. Instead, I get a grey box. I've even tried making a physically smaller image (256x256) and uploading that in its place, but it's still not showing up. Could the fact that it's in GIF format be the problem? I'm also behind a corporate firewall. Could that be part of the problem?

Here's a screen shot of what I'm seeing:

Update: I'm seeing other avatars, while others besides my own are blank (see screen shot), so it would seem that not all avatars are being hosted on imgur.com. This would seem to suggest that the problem can be solved on the site by not putting any avatars on imgur.com, where they would get blocked by corporate firewalls. (IMHO, all images should be hosted on a Stack Exchange URL, as not seeing them makes questions/answers that have images next to useless when seen from behind a corporate firewall that blocks imgur.com.)

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.